One Good Thing to Come of the Dot-Com Bust

Witness the dot-com boom and bust: a heady time toward the end of the millennium when venture capital funds flowed quickly into internet firms, company valuations were sometimes based on little more than web hits, launch parties boasted A-list celebs, and expectations (not to mention stock prices) were often unreasonably high. We know how that story ended, of course. Even as the champagne was uncorked, bubbles were burst, bankrolls were spent, and many companies failed—a cautionary time that's cast a long shadow ever since.

But from the ashes of the great dot-come flame out rose at least one mighty phoenix—the Optical Transport Networking (OTN), a set of standards for optical fiber communication.

OTN has become the ubiquitous transport technology globally. "Indeed it's hard to imagine any bit that goes over the internet doesn't at some point hop over a terrestrial or submarine optical network and get carried over this technology," said Stephen Trowbridge of Alcatel-Lucent, who gave a short course Sunday on new capabilities for routing signals via OTN in: #SC328, New Developments in Optical Transport Networking (OTN).

The short course focused on the first major revision of the standard since 2003, but the story he told along the way, on how OTN emerged more than a dozen years ago in the first place, was a fascinating yarn.

For many years communication standards were generally focused on carrying voice and fax information. Beginning in the mid-1980s things began to change as the industry moved to single-mode fiber, which had longer reach. Data started to enter the network, and soon new technologies began to be employed. Eventually Wavelength Division Multiplexing (WDM) emerged as a way of combining signals for transmission over fiber because it offered the advantage of decreasing the cost of long-haul transmissions and increasing capacity.

Around 2000, OTN was developed to help with this, Trowbridge said, because simply multiplexing optical signals over fiber fell short of the kind of network manageability and robustness that people in the field had been accustomed to with digital standards like SONET/SDH, Trowbridge said.

"Moving to WDN moved us back into the analogue kind of domain where we didn't have that kind of fault isolation," he added. The field wanted something that was carrier grade, would provide operation, administration and maintenance of networking functionality, would provide service transparency and would be client independent. The solution would be OTN, but its coming into being was somewhat unusual because it was designed to be a single, international standard.

"[OTN] was really the first transmission system that was developed as a global standard," Trowbridge said. This was different than what had been the reality for years in the field because there were regional differences -- say, between North America and Europe.

Blame the dot-com bust for that one, he added.

"Equipment vendors really weren't eager to go develop different products for different regions of the world," Trowbridge said. "They wanted to develop one product and sell it everywhere."

Among the topics he discussed, Trowbridge talked about how the standards moved from the first generation, operating at wavelengths around 2.5 to 10 Gb/s, to today's standards, which operate up to 100 Gb/s and the standards of tomorrow, where the wavelengths will be pushed even higher. He also covered IP and Ethernet mapping procedures and the architecture of the optical layer, which was updated in 2012.